Canary Trap

canary trap

A canary trap is a method for exposing an information leak, which involves giving different versions of a sensitive document to each of several suspects and seeing which version gets leaked. The term was coined by Tom Clancy in his novel ‘Patriot Games,’ though Clancy did not invent the technique. The actual method (usually referred to as a ‘Barium meal test’ in espionage circles) has been used by intelligence agencies for many years. The fictional character Jack Ryan describes the technique he devised for identifying the sources of leaked classified documents:

‘Each summary paragraph has six different versions, and the mixture of those paragraphs is unique to each numbered copy of the paper. There are over a thousand possible permutations, but only ninety-six numbered copies of the actual document. The reason the summary paragraphs are so lurid is to entice a reporter to quote them verbatim in the public media. If he quotes something from two or three of those paragraphs, we know which copy he saw and, therefore, who leaked it.’ A refinement of this technique uses a thesaurus program to shuffle through synonyms, thus making every copy of the document unique.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s